(if you think my spelling is bad in English, you oughta see my Gaelic! -- but I bet the spelling police would never have caught me if I hadn't turned myself in! :-D )
I'm still groggy or I might have. *\:-) But Gaelic is (generally) so easy...
But the pronunciation of "fiadachadh" seems rather far from "fiddich" -- the latter at least sounds like the genitive. Now you've made me pull out the Dwelly's and I find: "fiadhach" - hunting, esp. of deer.
(Shouldn't be getting into this now -- need to pack for vacation...)